New insight to magma emplacement and structural evolution of the northern Sistan zone

The late Paleocene – early Eocene granitoid intrusions in the northern Sistan suture zone are regarded as potential tools to record tectonic events. A structural study of the Zahri granitoid body, based on the anisotropy of magnetic susceptibility (AMS) technique provides new data to characterize the internal structure and the kinematic reconstruction. The NW–SE trending body consists basically granite to leucogranite. Based on the results of the analysis of over 360 samples collected from 36 sites, the granitoid body is characterized by a low susceptibility and petrographic observations indicate that paramagnetic minerals such as biotite and amphibole are the most important iron-bearing mineral and can be considered as the main carrier of magnetic susceptibility. Magnetic foliations dominated by moderate dip and foliation strike mostly parallel to the elongated shape of the body, the magnetic lineation mainly trends NE-SW to N-S with plunges to the SW (mean orientation N 197°/32°) and formed during the emplacement and crystallisation of the magma. The Zahri body emplaced in an extensional setting controlled by a NNE-SSW opening direction associated with spaces of the sinistral shear zone in the terminations of Nehbandan fault system during the early Eocene.